This invention relates to a tape cassette drive system which includes means for reducing the abrupt start-up shock to the tape upon the initial application of the tape transport force.
A storage medium finding increased use for the storage of digital information is a tape cassette. Digital cassettes are similar in construction to audio cassettes although with higher mechanical and electrical standards being maintained due to the relatively high data density recorded upon the tape. Prior to operation, a cassette is placed into the recorder with the drive and supply spindles engaging the drive and supply spools of the cassette. To facilitate alignment and engagement of the supply and drive heads of the tape drive system with the cassette spools, the heads are often spring loaded and pinned to their respective shafts for axial movement. Each of the heads define several radially projecting flutes with each flute defining a cam surface urging the heads into alignment with the tape spools.
A further consideration in providing such a drive system is the effect of abrupt acceleration on the tape during playback and record. Upon start-up, a portion of the relatively large inertial mass of the supply spindle as well as that of the cassette spool and tape carried thereon must be accelerated. The supply spool and supply spindle have considerable mass which is accelerated by the drive force coupled through the recording tape within the cassette. The forces created during start-up, stretch the tape. As the mass of the supply spindle and spool coupled to the tape is accelerated, a tape contraction follows due to overshoot of the supply reel followed by deceleration with an abrupt acceleration and corresponding tape stretch following. The net result is a slowly damped oscillation in the physical length of the tape. Such variations in the length of the tape introduce playback and recording signal errors unless a relatively long time period is accommodated to allow the oscillations in the physical length of the tape to become sufficiently reduced in amplitude. The apparatus to be described is directed to the reduction of such oscillations during start-up of a tape transport by incrementally coupling the inertial mass of the supply system to the tape.